I'm implementing a simple API flow which involves acting as a gateway to multiple upstream APIs.
Basically, a client provides a token to this endpoint, the server makes multiple sequential calls to APIs, gathers a bunch of information from the final call and returns it.
We receive a token, and go to Upstream API 1, receiving back a bunch of Objects associated with that token. There can be a theoretically unlimited amount of Objects returned.
We then comma separate the IDs of each Object, and go to Upstream API 2 with those comma separated ObjectIDs to receive further MetaInformation on all of the Objects.
This MetaInformation may not be unique to each Object, so we can receive anywhere between 1 and the number of ObjectsMetaInformation back.
The intention is then for us to go to a third API with the comma separated MetaInformationIDs, but this upstream API can only take 10 unique MetaInformationIDs, meaning that we wouldn't be able to collect the information the client is expecting. We therefore are able to throw a failure case at this point without making the failing upstream request, but what HTTP status is appropriate to use?
It doesn't seem like the client has made a bad request, as they would have no way of knowing the amount of unique MetaInformationIds at that point, but we would receive a 400 status were we to make a request with >10 MetaInformationIds.
Any ideas?
EDIT: I forgot to mention for context that the upstream API is intending to upgrade in the future to support >10 unique IDs, hence it has been decided that for now, a multi-request solution to that API is not worth it. I wholeheartedly agree that it is a sub-optimal solution.